N_2O在钾改性Cu-Co尖晶石型复合氧化物上的催化分解(英文)

Catalytic decomposition of N_2O over potassium-modified Cu-Co spinel oxides

制备了几个不同组成的Cu-Co尖晶石型复合氧化物,用于N2O分解反应,在活性较高的Cu0.8Co0.2Co2O4表面浸渍碱金属盐溶液,制备改性催化剂,考察了碱金属助剂类型、钾前驱物和钾负载量等对改性催化剂活性的影响。用BET、XRD、SEM、XPS等方法表征了催化剂结构。结果表明,几种碱金属碳酸盐改性Cu0.8Co0.2Co2O4的催化活性发生了显著变化,其中,K改性催化剂的活性有明显提高,而Cs的表面改性反而降低了催化剂活性;钾前驱物对K/Cu-Co的催化活性也有较大影响,其中,加入碳酸钾明显提高了催化剂的活性,而加入硝酸钾和醋酸钾反而降低了催化剂活性;有氧无水、有氧有水气氛中,400!C下N2O在碳酸钾改性催化剂0.05K/Cu0.8Co0.2Co2O4上的转化率分别达到了100%和87.6%;该催化剂在400!C下的恒温反应活性和稳定性均高于未改性催化剂。

Cu-Co spinel oxides with different compositions were prepared for N2 O catalytic decomposition in the presence ofoxygen. The active catalyst of Cu0. 8 Co0. 2 Co2 O4 was incipiently impregnated by alkali metal salt solutions to prepare the modifiedcatalysts. These catalysts were characterized by BET, XRD, SEM and XPS techniques, and their catalytic activity for N2 Odecomposition was tested. The effect of alkali metal species, potassium precursors and potassium loadings on catalytic activity wasinvestigated. It was found that the catalytic activity of Cu0. 8 Co0. 2 Co2 O4 modified by K2 CO3 was much higher than that of bareoxide, while Cs / Cu0. 8 Co0. 2 Co2 O4 was inferior to Cu0. 8 Co0. 2 Co2 O4 for N2 O decomposition. In the case of K / Cu0. 8 Co0. 2 Co2 O4 withdifferent potassium precursors, the catalyst activity was largely enhanced by the addition of K2 CO3 , while the doping of KNO3 andCH3 COOK notably depressed the catalytic activity. Over the optimal catalyst of 0. 05K / Cu0. 8 Co0. 2 Co2 O4 , 100% and 87. 6%conversion of N2 O was reached at 400 ℃ under the atmosphere of oxygen only and oxygen-steam together, respectively. Inaddition, K2 CO3 -modified catalyst in both reaction atmospheres showed higher stability than un-modified catalyst.